Metastasis is the leading cause of death from prostate cancer (PCa) and there is a compelling need to find effective treatments for metastatic disease. Theranostic imaging, where diagnosis is combined with therapy, is particularly suitable for a disease that is as complex as cancer, especially now that genomic and proteomic profiling can provide an extensive fingerprint' of each tumor. The two aims in this research component converge towards developing theranostic nanoplex platforms for treatment of metastatic PCa. In Aim 1 First-in-man' clinical studies will evaluate prostate-specific membrane antigen (PSMA) based detection of metastatic PCa using positron emission tomography (PET). These clinical studies are the successful culmination of research initiated through an ICMIC pilot project awarded to Dr. Pomper in 2003. In Aim 1 we will perform a first-in-man study of [18F]DCFBC in metastatic PCa as well as a preliminary comparison of its ability to detect metastatic disease with that of [11C]choline. Proof-of-principle preclinical studies will be performed in parallel in Aim 2, to develop and optimize a theranostic PSMA-targeted prototype nanoplex carrying multimodality imaging reporters together with small interfering RNA (siRNA) and a prodrug enzyme. Each component of the nanoplex is carefully selected to allow us to evaluate each of its aspects i.e., image-guided delivery of nanoplex, siRNA-mediated downregulation, and conversion of prodrug to cytotoxic drug by the prodrug enzyme, with noninvasive imaging. These clinical and preclinical studies will identify new effective image-guided strategies to achieve cancer cell-specific treatment for metastatic PCa. In this era of personalized molecular medicine, the effective implementation of theranostic agents may achieve successful treatment for metastatic PCa, a goal that remains elusive despite the technological advances of the 21st century.